Such apparatus is described in U.S. Pat. No. 2,832,368, and may be used to supply fuel to n injectors, but when the fluid flow characteristics of each direction are not identical, e.g. unmatched pairs of burners, burners with differing degrees of dirt deposited on them, etc.. equal amounts of fuel are not delivered to each burner.
Preferred embodiments of apparatus in accordance with the invention enable gas to be more equally distributed.